The SUMO Source for MBE is the optimal source technology for Group III evaporation. The SUMO design features a dual filament heater tailored to a uniquely shaped crucible. With gallium and indium, the source is operated in hot-lipped mode to eliminate material recondensation at the crucible orifice, and thereby reduces oval defects. A heat-shielding cap enhances the source’s efficiency and minimizes the thermal load on the system. The SUMO Source offers excellent flux stability and uniformity along with a significantly increased charge capacity.

The unique patented crucible features:

A cylindrical reservoir for large charge capacity and minimized long-term depletion effects

A small tapered orifice for optimal flux distribution and negligible shutter flux transients

SUMO Sources are available optimized for any MBE system. For some systems, the SUMO crucible features an asymmetric orifice and offset exit cone to redirect the beam flux for enhanced thickness uniformity across the rotated substrate. Due to the wider exit cone, the asymmetric SUMO does not use a separate heat-shielding cap at the crucible lip.

Performance and Benefits

SUMO Sources provide the largest available Group III charge capacity without sacrificing material quality or source performance. Facilities worldwide have demonstrated excellent material quality with good thickness uniformity across the substrate.

Benefits include:

Large charge capacity. Compared to the original Group III sources from other vendors, the Ga or In charge capacity may be doubled. The SUMO Source size refers to the actual amount of source material that can be loaded is dependent on system geometry and source port location. For example, a 4500g SUMO Source may be loaded with either 4500g of gallium or 5500g of indium.

Good uniformity. SUMO Sources are designed to meet or exceed the thickness uniformity (±1%) achieved in most MBE systems with the originally recommended sources.

Long-term flux stability. With its unique shape, the SUMO crucible minimizes the long-term depletion effects commonly seen with conical crucibles. The SUMO Source presents a constant melt surface for more consistent and reproducible day-to-day operation. A constant beam flux is maintained with smaller and less frequent temperature changes.

Low defect densities. Hot-lip heating with a dual filament source ensures that the crucible orifice is sufficiently warmer than the melt temperature to prevent gallium and indium droplet formation. Measured defect densities for material grown with a SUMO-Reduced shutter-related flux transients. The melt surface, recessed behind the small orifice of the SUMO crucible, is shielded from most reflected radiation. Heat reflected back from closed shutters is diffused by the PBN crucible without causing the shutter flux transients commonly seen with conventional open crucibles.

Excellent material quality. PBN crucible construction and small crucible orifice, coupled with efficient dual filament heating, reduces the thermal load on the surrounding system and leads to lower background impurities in the grown layers.